Availability of large plant collections of genebanks for use is determined to a great extent by the level of knowledge accumulated about stored biomaterial. For this purpose, collections by traits are created as a result of long-term studies of genotypes by complex of parameters at all ontogenesis stages. Extreme conditions of year 2012, i.e. abnormal heat and prolonged drought, allowed performing evaluation of maize lines by their resistance to these abiotic factors. Special attention was paid to the development of plants in generative phase. This period is the most important for yielding of grain. High temperature and low humidity of the air reduce viability of pollen and also negatively affect pollination and grain content in maize cobs. Humidity deficit in generative phase of plants influences the production of underdeveloped flowers and asynchronous flowering [1].  The delay in flowering of female and male inflorescences or protandry in maize is not long under favorable conditions. Under the influence of abiotic stress this delay can become significantly longer in some genotypes. As a result of this, part of female flowers is not pollinated and maize cob remains imperfect [2].  Studied material included 8 high-lysine maize lines (Chișinău Н.О о2 434, Ch. - 433 Ch.- 2192, Ch. - 245, Ch.- 424, Ch. - 253, Ch. -221, Ch.-235-2) from collection of the Center for Plant Genetic Resources of Moldova.  For selection of lines for resistance, the main parameters of generative phase were considered: protandry duration, pollen production ability of panicles, number and length of maize stigma.  As a result of phenological observations, genotypic differences were revealed with regard to duration of period from seedlings to flowering of male inflorescences. Beginning of flowering of panicles was recorded upon the appearance of more than 20% anthers in half of recorded plants. Trait variability was noted within 50 days (lines: Ch.-  219 -2 Ch-  424) to 58 days (Ch.- 253, Ch.- 221). Flowering of female inflorescences began when not less than 10-20 stigmas appeared from the cornhusk. Duration of the period from seedlings to flowering varied within 52 days (lines Ch.-424) to 62 days (Ch.-253). Line Сh.221 was noted for full absence of stigmas and reduced maize cobs. So, under the influence of stress, the asynchrony of flowering increased in all 8 lines of maize. At that, protandry of line Сh- 424 was 3 days (minimum value) and the longest delay was recorded for lines Сh. - 253 (5 days) and Сh.- 221 (full absence of stigmas).  Number of stigmas and their length were recorded on the first, third and fifth day after their appearance from the cornhusk. Further, the average values were found from these three measurements. Line Ch-434 had the most intensive flowering of maize cob (54 stigmas with the average length of 6.8 cm.), a few short stigmas were observed in line Ch-253 (8 stigmas with the average length of 2.3 cm.) and line Ch-221 had no stigmas at all. Other lines were characterized by the intermediate values of parameters. For evaluation of lines by pollen production ability, a 6-point scale was used considering weight of pollen from one collection for pollination. Comparative analysis of obtained data allowed revealing significant genotypic differences; lines were divided into two groups. The first group included 3 lines with high level of parameter (5-6 points): Сh- 224, Сh- 219, and Сh- 433. In second group of lines plants developed reduced panicles that resulted in significant decrease of the amount of pollen (1-2 points).   Thus, as a result of evaluation of 8 high-lysine maize lines by resistance to high temperatures and humidity deficit, some parameters of generative phase of plants were studied. Genotypic differences were revealed with respect to response to stress (prolonged protandry, decreased pollen production ability, reduced development of male and female inflorescences). After collation of the results by productivity, the line Chișinău Н.О о2- 424 was selected as the resistance donor.